Why are we able to chew food without biting ourselves?

[TreacherousCretin]

(Mary Roach, “The Marvels in Your Mouth”
New York Times 3-25-2013)

*Think of a peanut between two molars, about to be crushed. At the precise millisecond the nut succumbs, the jaw muscles sense the yielding and reflexively let up. Without that reflex, the molars would continue to hurtle recklessly toward one another, now with no intact nut between.

To keep your he-man jaw muscles from smashing your precious teeth, the only set you have, the body evolved an automated braking system faster and more sophisticated than anything on a Lexus. The jaw knows its own strength. The faster and more recklessly you close your mouth, the less force the muscles are willing to apply. Without your giving it a conscious thought.*

[Machine_Elf]

@TreacherousCretin

To keep your he-man jaw muscles from smashing your precious teeth, the only set you have, the body evolved an automated braking system faster and more sophisticated than anything on a Lexus. The jaw knows its own strength. The faster and more recklessly you close your mouth, the less force the muscles are willing to apply. Without your giving it a conscious thought.*

When this system screws up, it hurts. If you’ve ever accidentally bitten a fork, you know that it’s about as painful as biting your cheek/tongue - except it’s your teeth that end up hurting.

[PoppaSan]

@aceplace57

Biting my cheek is my most common mistake. Happens a few times a year. Biting my tongue is much less common. Maybe once a year. That’s just my own experience.

I’m having trouble comprehending an adult (presumed on my part) biting their cheeks and tongue several times a year. I can’t recall the last time I bit my cheeks and the tongue was once maybe 4 years ago.

[aceplace57]

I don’t know why it happens either.

I’d guess I was eating too fast or not paying attention. But it’s not unusual to eat quickly. I usually don’t bite myself.

It doesn’t happen that often. It’s painful when it does.

[LSLGuy]

@PoppaSan

I’m having trouble comprehending an adult (presumed on my part) biting their cheeks and tongue several times a year. I can’t recall the last time I bit my cheeks and the tongue was once maybe 4 years ago.

Eating while thinking of something else, while talking, or while walking, bending over, twisting, etc., are all ways to increase the odds of a bite. As are taking mighty bites, chomping once, then swallowing.

Some people eat like that only seldom. Others do it that way most of the time.

[Arrogance_Ex_Machina]

@PoppaSan

I’m having trouble comprehending an adult (presumed on my part) biting their cheeks and tongue several times a year. I can’t recall the last time I bit my cheeks and the tongue was once maybe 4 years ago.

Earlier this year I bit my cheek really badly while asleep. Adult or not there’s not much you can do to avoid that.

[Jennshark]

Perhaps it’s some kind of brain motor controllish thing. After having a few seizures four+ years ago I went through about six months of uncontrolled chomping down on my tongue and cheek walls – especially when talking.

It happens far less now, but I am much more prone to doing this post-seizures. Maybe the fits blew out a teeny part of my brain that controls the teeth-tongue-cheek circuitry

[Leo_Bloom]

@Tired_and_Cranky

I’m sitting here eating roasted pumpkin seeds and I realized that I do no**thing like this. The tip of my tongue is pressed firmly into the hollow into the roof of my mouth while I chew a seed with my molars.

Doing it your way felt really awkward, like trying to write with my left hand. I also almost bit my tongue after only two seeds.

A diagram of the neuromuscular mechanism involved in the act of chewing food, from Kapur, K. K., H. H. Chauncey, and I. M. Sharon. 1966. "Oral physiological factors concerned with ingestion of food, in Nutrition in Clinical Dentistry (A. E. Nizel, ed.), 2nd ed., pp. 296–304 (Saunders: Philadelphia).

It is cited in the fascinating Food Texture and Viscosity: Concept and Measurement, Bourne, Malcolm C., 2nd ed., p. 44 (Elsevier: London).

[Years ago I posted an OP query on how they measure the snap-crackle-and-pop of Rice Krispys, little knowing how far I’d go in searching the topic]

[Leo_Bloom]

This diagram on how quickly and where food goes down the hatch, also from the work cited above, and I’m too tired to give the full reference, is actually more to the point of

@Tired_and_Cranky

I’m sitting here eating roasted pumpkin seeds and I realized that I do nothing like this. The tip of my tongue is pressed firmly into the hollow into the roof of my mouth while I chew a seed with my molars.

Doing it your way felt really awkward, like trying to write with my left hand. I also almost bit my tongue after only two seeds.

The physics of food and chewing it and slurping it is covered in this book to a fare-the-well, if anyone needs numerical backing to the evolutionary discussion.